Fixing suspend in Xiaomi Mi Notebook Air

The common issue in my notebooks: suspend (sleep to RAM) stops working every
second time. I.e., the first time I close the lid, the laptop falls asleep,
open lid awakens, but the second time is unsuccessful. Either no suspend,
or no wakeup. The cure in C720
was to unload TPM
manually.

Earlier I did this dropping a script into /usr/lib/systemd/system-sleep/.
But manual page says this was a hack, there could be a nicer interface used
for that. Arch wiki
suggested creating a systemd unit to be executed prior suspend. So did I
in my Xiaomi Mi Notebook Air: